Process for preparing benzanthroneacridine dyes and dyeing cellulose fibers



United States Patent 3,254 935 PROCESS FOR PREPARING BENZANTHRONE- ACRIDINE DYES AND DYEING CELLULOSE FIBERS Joseph Deinet, Woodclitf Lake, N.J'., assignor to E. I. du

Pont de Nemours and Company, Wilmington, DeL, a

corporation of Delaware No Drawing. Filed Mar. 19, 1962, Ser. No. 180,806 4 Claims. (Cl. 834) On alcoholic caustic alkali fusion, the benzanthronylaminoanthraquinone was converted to the benzanthroneant-hraquinoneacridine of the formula:

The benzanthronylaminoanthraquinone compounds, prior to ring closure, have been considered to be of little value as vat dyes in themselves, and in general even the ring closed dyes are used only as dyeing colors and are not usually employed in the application to textiles by printing procedures.

While certain imino compounds in this class when sulfonated have been applied to wool and related fibers, in

general it was only when they carried an arylamino substituent which is normally more readily sulfonatable than the anthraquinone and benzanthrone nuclei in the molecule.

It is an object of the present invention to provide a process for applying benzanthronylaminoanthraquinone compounds to cotton in the form of water-soluble sulfonic acid derivatives which when subjected to any of the normal vatting procedures are ring closed to the benzanthroneanthraquinoneacridine dyes which dye cotton and related fibers in substantially the same fast shades ranging in color from green to greenish-gray to black, as the corresponding acridine compounds which have been ring closed by alcoholic-caustic alkali fusion prior to vatting. It is a further object of this invention to provide a method for effecting ring closure of benzanthronylaminoanthraquinone compounds by first sulfonating the compounds directly in the anthraquinone and/ or benzanthrone nuclei and then reacting these sulfonic acid derivatives in solution, which may or may not contain a textile fiber to be dyed, with an aqueous alkaline reducing agent.

According to the present invention, water-soluble benzanthronylaminoanthraquinones, which contain from 1 to 3 sulfonic acid groups directly attached to the benzanthronyl and/or the anthraquinone radicals, are converted to the benzanthroneanthraquinoneacridine dyes by vattingjn aqueous caustic alkali with an alkali metal hydrosulfite. This may be in the presence or in the absenceof the fiber to be dyed.

The sulfonic acid compounds used in this invention are prepared by carrying out the sulfonation of the benzanthronylaminoanthraquinones in sulfuric acid ranging from 100% (monohydrate) to 65% oleum at temperatures of from about 15 to 30 C. The sulfonation may be carried out using from 4 to 10 parts by weight of the sulfonating acid per part of the benzanthronylaminoanthraq-uinone, although smaller amounts may be used with a diluent such as 2 to 3 parts of chlorosulfonic acid. When sulfuric acid monohydrate or low percent oleum are used, temperatures of from 20 to 30 C. may be employed, although with sulfuric acid of higher oleum content temperatures of from 15 to 25 C. are usually preferred. Sulfonation is continued until a test sample taken from the sulfonation mass is found to be watersoluble. This usually takes from 4 to 24 hours. In using these products to dye cotton, it is often desirable to have the solubility such that a test sample is not readily soluble in cold water but is readily soluble in water at or near the boiling point. If the sulfonation has been carried too far so that the resulting products are too soluble in water, the sulfonic acid content may be reduced by heating the sulfonated products after the concentration of the acid is reduced with water or dilute sulfuric acid to from about to at from 45 to 60 C. for a period of from 3 to 6 hours or until a test sample is relatively insoluble in cold water but soluble at the boiling point.

The sulfonic acid derivative-s are isolated by the usual methods such as by drowning in water and salting the sulfonation mass, filtering off the sodium sulfonate form of the dye, and washing it with dilute salt solution until free of acid. The filter cake may be either dried and used as a powder, or converted to a dye paste by ordinary milling in which dispersants or wetting agents may be incorporated.

The dyes contemplated for use in the present invention are the water-soluble sulfonic acid'derivatives of benzanthronylaminoanthraquinone compounds having the general formula:

in which Bz stands for benzanthronyl, Aq for anthraquinonyl and X stands for hydrogen or a radical of the group consisting of -NH-Bz, -NHAq, -NH-Bz-NH-Aq,

3 -NH-Aq-NH-Bz and -NH-Aq-NH-Aq, each benzanthronyl radical in said compounds forming with an aminoanthraquinonyl radical a nucleus of the formula:

in which X stands for the same as above, there being not more than three Bz radicals and not more than a total of five A-q and Bz radicals in each complete molecule; in

. each case where the benzanthronyl radical is attached to a second anthraquinonyl radical in the molecule, it is through its 9-position to an alpha position of said second anthraquinonyl radical; the anthraquinonyl radicals when connected to each other directly through -NH- are through alpha-alphaor alpha-beta-imino linkages, and simple substitution products of said benzanthronylaminoanthraquinone compounds such as NH CH -B-r, C1, -NHCOC H said substituents' being non-sulfonatable in these compounds under the conditions employed and prior to sulfonation there being no substituent in the rings A and B; said compounds containing from 1 to 3 sulfonic acid ($0 M) groups, there being at least one sulfonic acid group per'benzanthronyl radical in the molecule, in which M stands for H, alkali metal (more particula-rly Na and K) and ammonium.

The solubilities of these dyes may be varied to some extent by modifying M in the above formula.

The free sulfonic acid and the alkali metal and ammonium salts of the sulfonic acids may be produced by employing the techniques usually employed in the manufacture of sulfonic acid compounds in the anthraquinone sulfonic acid dye field.

While it has not yet been proved, it is believed that in the sulfonation of the benzanthronylaminoanthroquinones at least one sulfonic acid group is in either the 4-position of the benzanthrone nucleus or the 2-position of the anthraquinone nucleus adjacent the imino radical, for it is surprising that by a simple vatting procedure the acridine ring is produced, thereby converting the benzanthronylarninoanthraquinone into the acridine dye. This ring closure has heretofore been carried out only under very strenuous conditions such as with an alcoholic alkali fusion.

The water-soluble sulfonic acids of this invention may also be ring closed to produce the olive-to-gray-to-black vat dyes by applying other alkaline reduction procedures such as by reacting with zinc and sodium or potassium hydroxide, or by reaction with hot aqueous polysulfides (Na S in which x stands for 2 to 6, or by the caustic alcohol treatment generally referred to in this art as alkaline fusion.

The benzanthronylaminoanthroquinones of the general formula given above and which are used in the following examples, are prepared by the usual Ullmann method of condensing halogen benzanthrones with aminoanthraquinone compounds, including amino-dianthrimides obtained by condensing halogen anthraquinones with aminoanthraquinones to form diimides. In general, these condensations are carried out in a solvent such as nitrobenzene at temperatures of from 150 to 250 C. in the presence of a copper catalyst such as copper acetate and in the presence of an acid binding agent such as sodium carbonate, potassium acetate or mixtures of these or other acid binding agents, all of which is well known in the art.

. Serial No. 180,807 filed of even date herewith, will dye cellulosic fibers from the usual alkaline hydrosulfite vat or by any of the usual vat dyeing or vat printing processes in greenish and gray-to-black shades. In each case, it is desirable that the sulfonated product contain from 1 to 3 sulfonic acid groups ($0 M)v with at least one such sulfonic acid group per benzanthrone radical in the molecule. Further detailed methods for carrying out the condensation of the benzanthrone and anthraquinoue compounds and for producing the sulfonic acid derivatives of the compounds which may be used in the present invention are found in my co-pending application Serial No.

180,807 above-mentioned.

' In the general formulae used in this specification to indicate particular benzanthronylaminoanthraquinones, B2 and Aq designate benzanthonyl and anthraquinonyl radicals, respectively, and the number at each side of the NH group or next to a substituent group indicates the point of attachment to the adjoining 'benzanthronyl and anthraquinonyl radical.

The following examples are given to more fully illustrate the invention.

Examples 1 to 3 are given to more specifically illustrate the preparation of the class of water-soluble benzanthronylaminoanthraquinone sulfonic acid compounds which are employed according to the present invention in the dyeing of cellulose material, or which may be converted to the benzanthroneanthraquinoneacridine dyes, by a simple vatting procedure.

' Example 1 Fifty (50) parts of the benzanthronylaminoanthraquinone compound, prepared as described in the example of U.S. Patent 2,456,589 in column 3, lines 1 to 52, are dissolved in 250 parts of 25% oleum at 25 C. and the solution is stirred for 16 hours at this temperature to give a product which is soluble in cold water. The sulfonation mass is then poured into 1500 parts of cold water. The drowned mass is stirred 1 hour, treated with 150 parts of sodium chloride, and stirred at 40 C. for 2 hours. The sulfonation product is filtered off and washed acidfree with a 10% solution of sodium chloride. The dye thus obtained contains from 1 to 2 SO Na groups and dyes wool from a hot acidic aqueous dye bath in yellowbrown shades. It also dyes and prints cotton in gray shades from an alkaline hydrosulfite vat by any of the processes herein described.

Example 2 Fifty (50) parts of 1-(3-benzanthronylamino)-anthraquinone are dissolved at 10 to 12 C. in 125 parts of chlorosulfonic acid and agitated at this temperature for 0.5 hour. 125 parts of 25% oleum are added in portions over a period of 0.5 hour at 10 to 12 C. to give approximately a disulfonic acid which is soluble in water. The mass is stirred at this temperature for 3.5 hours. The sulfonation mass is poured into 1300 parts of a mixture of crushed ice and Water. After stirring .the drowned mass for 1 hour, it is heated to C., parts of sodium chloride are slowly added, and the slurry is agitated until the temperature drops to 45 C. The precipitate is filtered off, washed acid-free with a 10% sodium chloride solution, and dried. The sulfonated 1-(3-benzanthronylamino)-anthraquinone thus obtained dyes wool in orange-brown shades from a hot acidic aqueous dye bath, and dyes and prints cotton in green shades in the presence of alkaline hydrosulfite at steam temperatures at atmospheric pressure.

Example 3 Forty (40) parts of l-amino-S-(3-benzanthronylamino)-anthraquinone, preparedby subjecting equal molar proportions of 3-bromobenzanthrone and 1,5-diaminoanthraquinone to the conventional Ullmann condensation procedure as described above, are dissolved at 20 to 25 C. in 200 parts of 25 oleum. The solution is agitated at 25 C. for 6 hours, at which time a test sample is quite soluble in distilled water. After standing for 10 hours, the solution is poured into 1200 parts of cold water. The drowned mass is stirred for 1 hour at 50 C., treated with 100 parts of sodium chloride, and stirred for 2 hours longer at this temperature. The precipitate is filtered off at room temperature, washed acid-free with a 15% sodium chloride solution, and dried. The product thus obtained is represented by the formula:

and dissolves in concentrated sulfuric acid to give a redviolet solution, whereas the concentrated sulfuric acid solution color of the condensation product used as starting material is orange-brown. The sulfonated product dyes wool in orange-brown shades from a hot acidic aqueous dye bath, and prints cotton in gray shades by any of the processes hereinafter described.

Example 4 A mixture consisting of 450 parts of nitrobenzene, 44.6 parts of l-aminoanthraquinone, 77.6 parts of 3,9-dibromobenzanthrone, 22 parts of sodium carbonate, 11 parts of potassium acetate and 3 parts of copper acetate is agitated at 170 C. for 12 hours. After cooling to 60 C., the condensation mass is diluted with 400 parts of methanol and filtered. The filter cake is washed with methanol and hot water, in turns, and dried.

Forty (40) parts of the product thus obtained are dissolved in a mixture of 80 parts of chlorosulfonic acid and 40 parts of oleum at 15 C. After'stirring for 0.5 hour, 40 parts of 25 oleum are added in portions over a period of 0.5 hour. The mass is stirred for 5 hours at 21 C., 40 parts of 25 oleum are added and stirring is continued for 6 hours. After standing for ll hours, the sulfonation mass is poured into 1200 parts of a mixture of ice and water and stirred for 0.5 hour. The drowned' slurry is heated to 70 C., 100 parts of sodium chloride are slowly added, and the whole is stirred while cooling to C. The precipitate is filtered off, washed 6 acid-free with a 10% sodium chloride solution, and dried. The product thus obtained is represented by the formula:

It dyes wood in orange-brown shades from a hot acidic aqueous dye bath, and prints cotton in olive shades by any of the processes described below.

' The following example illustrates the ease with which ring closure of the sulfonic acid compounds employed in this invention takes place under ordinary vatting condi- .tions.

' Example 5 Thirty (30) parts of 3,9-bis(l-anthraquinonlyamino) benzanthrone are dissolved in a mixture of 60 parts of chlorosulfonic acid and parts of 25 oleum at 18 to 20 C. and the solution is stirred for 10 hours at 20 C. After standing over night, a test sample .of the sulfonation mass dissolves in water to form a clear solution. Then 90 parts of 50% sulfuric acid are added at 3 to 6 C. over a period of 5 hours. After standing over night, the mass is slowly heated (over 1.5 hours) to 50 to 52 C. and agitated at this temperature for 3 hours. A test sample is now quite insoluble in cold water. The mass .is cooled to 22 C., poured into 1000 parts of cold water, and stirred for 2 hours. The product is filtered off, and washed acid-free'with a 2% solution of sodium chloride.

One (1) part of-the above filter cake is slurried in 50 parts of water, and 5 parts of sodium chloride are added. After agitating the slurry at 25 C. for 0.5 hour, the precipitate is filtered olf, washed with a 10% solution of sodium chloride until the filtrate is sulfate-free (BaCl test), and dried. The resulting product, of the formula:

70 to 75 C. until there is no longer a color bleed on filter paper. The precipitate is filtered off, washed with hot water until free of alkali and sulfate, and dried. A vat dye is obtained which is represented by the formula:

It contains nitrogen and sulfur in the ratio: N:S=2:0.34. These analyses show that one sulfo group was lost during the ring closure reaction.

The properties of the above-described wool and vat dyes are tabulated, along with those of the dye of Color Index 69,525, as follows:

Any of the water-soluble benzanthronylaminoanthraquinone compounds formulated above and further illustrated herein and in my co-pending application Serial No. 180,807 may be ring closed to the vat dye by the above or other known alkaline vatting procedure.

The following examples illustrate that the usual vat dyeing and printing methods employing temperatures normally used in the dyeing of vat dyes in general, apparently effect ring closure of the sulfonated benzanthronylaminoanthraquinone compounds to the corresponding acridines and dye them on cotton fibers to give substantially the same shades as the corresponding benzanthroneanthraquinoneacridines when produced by alcoholic caustic fusion.

Cotton piece goods may be dyed by the sulfonated benzanthronylaminoanthraquinones according to this invention by the pad steam process more particularly described -in U.S. Patent 2,487,197 (except that in the present case the dye is used as an aqueous solution of the sulfonic acid derivative in place of a vat pigment in the dye padding step).

Example 6 The su-lfonated benzant-hronylaminoanthraquinone compound used in this example is prepared by dissolving 50 parts of Bz-3-NH-I-Aq-S NH-2-Aq-3OH (see Example 1 of U.S. Patent 2,505,234) in 250 parts of 25% oleum at 14 to 16 C., stirred for 11 hours at 23 C and allowed to stand over night. 65 parts of water are added slowly at to 20 C. After stirring the mass at 15 to 20 C. for 0.5 hour, it is stirred at 53 C. for 4.5 hours, cooled to 20 C. and poured into 1500 parts of cold water. After slowly adding 50 parts of sodium chloride to the drowned mass at 70 C.,it is cooled to 22 C. The sulfonated product is filtered off and washed acidafree with a 2.5% solution of sodium chloride and dried. The product thus obtained contains from 1 to 2 sodium sul-fonate groups per molecule.

Cotton twill fabric is run through a padder at 60% pick-up, that is, the squeeze rolls are set so that the fabric retains 60%, based on the weight of the fabric, of the following dye solution.

padded at 90% pick-up with the following chemical pad solution:

6.0 ounces of sodium hydroxide, and 6.0 ounces of sodium hydrosulfite in 1.0 gallon of water.

The temperature of the chemical pad bath is 90 F. and

the immersion time is 5 seconds.

The impregnated fabric is then passed through a substantially oxygen-free steam chamber (2l2-2l5 F.) for a duration of 30 seconds. The dye is in reduced form upon leaving the steamer, and is subsequently oxidized in conventional manner in 0.25% sodium perborate solution. The dyed fabric is then rinsed in cold water, soaped, rinsed and dried.

The resultant fabric is dyed a level gray shade and exhibits excellent fastness to washing and to light. The shade and strength obtained are comparable to those of the benzanthronea'cridine dye obtained in the methanolic- KOH fusion process described in Example 1 of U.S. Patent 2,505,234.

Similar results are obtained in the dyeing process of the present example when the drying step which follows the dye padding step is omitted, or when the chemical pad-steam portion of the process is replaced with an alkaline lhydrosulfite reduction in a jig or Williams unit in the conventional manner; see pages 109 and 120, respectively, in The Application of Vat Dyes, AATCC Monograph No. 2, American Association of Textile Chemists and Colorists, 1953.

The dyeing methods described in this example may also be used for applying other sulfonated benzanthroneacridine dyes, including those of the dianthrimide type described above as well as the triand higher poly-anthri'mide type water-soluble dyes described in my copending application Serial No. 180,807. Shades on cotton are obtained from a number of these dyes as shown in the following table.

Examples 7 and 8 illustrate the dyeing of yarn with the water-soluble benzanthronylaminoanthnaquinone sulfonic acids by the well-known package dyeing process as more particularly described in the AATCC Monograph above-cited, starting on page 86, using both the pigment method and the reduced method at varying temperatures.

Shade on cotton Olive Olive Example 7 A l-pound package of single ply cotton yarn is placed in the kier of a single package machine equipped with an expansion tank of ample size to accommodate the final dye bath liquor volume of 1.3 gallons which is employed. Water at F., 1.3 gallons, is circulated through the package for 15 minutes. The water is discarded, and the package is rinsed with warm water, which is also discarded. Then 0:32 ounce of the dye powder having the general formula (Aq-1-NH-9-Bz-3-NH-l-A-q)-(SO Na) is added to 1.1 gallon of water at 180 F. and the dye solution is circulated through the package at 180 F. for

20 minutes. 2.6 ounces of sodium hydroxide, dissolved in 0.1 gallon of cold water, are added over a period of 10 minutes, followed by the addition of 2.6 ounces of sodium hydrosulfite dissolved in 0.1 gallon of cold water, during 10 minutes. 1 The direction of flow through the package is reversed each 5 minutes throughout the'process. Circulation at 180 F. is continued for 30 minutes after the sodium hydrosulfite has been added. The 4 ounces of sodium chloride are added over a period of 30 minutes while circulating, and the dye liquor is discarded. The package is rinsed with water until free of alkali, then oxidized by circulating 1.3 gallons of water containing 0.24 ounce of sodium perborate for -15 minutes at 120 F. 0.13 ounce of the sodium salt of a long chain alkyl sulfate is added at 205 F., circulation is continued for 15 minutes, and the bath is discarded.

The pack-age is then rinsed with warm water, centrifuged I and dried.

A level dyeing is obtained which is similar in shade to that obtained by similarly dyeing a package of cotton yarn at 140 F. with a sample of Cl. Vat Black No. 25, Q1. 69,525.

Example 8 A l-pound package of single ply cotton yarn is placed in the package dyeing machine, and hot water, followed by warm water, are circulated as described in Example 7. 1.15 gallons of water containing 1 ounce each of sodium hydroxide and sodium hydrosulfite, are circulated through the package for minutes at 110 F. 0.8 ounce of the dye obtained in Example 2 is reduced in 015 gallon of water at 140 F. for minutes with 0.3 ounce each of sodium hydroxide and sodium hydrosulfite. The leuco dye solution is added to the machine and dyeing is started at 110 F., gradually raising the temperature to 140 F., changing the direction of flow every 5 minutes. After '30 minutes at 140 F., 4 ounces of sodium chloride are added over a period of 30 minutes and the dye liquor is discarded. The package is rinsed, oxidized, soaped, rinsed, centrifuged and dried as described in Example 7. A level green dyeing is obtained which is similar in shade to that obtained from C.I. Vat Green No. 3, Cl. 69,500.

The optimum temperature for the package dyeing process of these water-soluble benzanthronylaminoanthraquinone sulfonic acids will vary somewhat due to the particular constitution of the dye. While many of the dyes of this class can be dyed in package dyeing machines at temperatures of 140 F., more complete dyeing of some will require temperatures closer to 180 F. In some cases temperatures as high as 205 to 250 F. may be employed.-

The following example illustrates the application of the class of dyes of this invention to cotton fabrics by the usual printing processes, in which it will be noted that the usual conditions are employed for the vatting and application of these soluble dyes.

Example 9 Mercerized cotton muslin is printed by the following procedure. Thickener for the printing paste .is prepared from the following ingredients:

1000 parts The wheat starch and British gum are mixed with 358 parts of cool water, then stirred while boiling for 30 minutes. Water lost by evaporation is replaced. The potassium carbonate is added at 180 P. Then, at 140 F., the

10 sulfoxylate, glycerol and the remainder of the water are added. The thickener is slowly cooled to 70 F., with stirring, then strained.

The printing paste is prepared by adding slowly, with stirring, until a uniform paste is obtained,

85.0 parts of the above thickener to a mixture of 8.6 parts of water and 6.4 parts of the dye prepared as described above in Example 2 100.0 parts This printing paste is printed on cotton muslin fabr c from the conventional textile printing equipment, using engraved rolls or plates. The printing may be either in patterns or overall applications to solid shades, and either on one or both sides of the fabric.

Development and fixation is accomplished by steaming in a Mather and Platt ager (a continuous steaming chamber, see the AATCC Monograph No. 2, page 188, 195 3), for from 5 to 10 minutes at from 218 to 220 F. The reduced prints are then oxidized by passing the fabric through a bath containing 5 parts of sodium dichromate, 5 parts of acetic acid and 990 parts of water at F. for about 1 minute. The printed fabric is then rinsed with clear water, soaped, again rinsed, and dried.

Strong, clear, green prints having excellent fastness properties are obtained. The shade is brighter, and the tinctorial strength is surprisingly greater, on equal molar basis, when compared with the control prints of the previouslyring closed acridine; see Color Index Vat Green No. 3, Cl. 69,500, when made by alcoholic caustic potash 'fusion of 1-(3-benzanthronylamino)-anthroquinone, es-

. Shade of print Dye used:

on cotton Dye of Example 3 above Gray (Aq-1-NH-9-Bz-3-NH-l-Aq)-(SO Na) Olive. Dye of Example 4 above Olive (Bz 3 NH -1- Aq 5 NH-- 2-Aq-3-CH -(SO3N3.)2 3 Gray Similar results are obtained when other printing methods are employed, such as those used in the printing of any cellulosic textile material or other textiles which can normally be dyed with vat dyes in the customary manner, namely, those which are not deleteriously affected by alkali metal carbonates or caustic alkalies in the presence of reducing agents in the concentrations and at the temperatures employed in the development of the vat dyes. Other printing methods which may be advantageously used include printing with a water-in-oil emulsion system as described in US. Patent 2,907,624, or by the process of US. Patent 2,587,905.

The sulfonated benzanthronylaminothraquinone compounds are conveniently applied according to the present invention to cellulose fabric for the production of level, speck-free, heavy or light shades, particularly by the pigment pad method, without the need for preparing vat dye pigments in special physical form since the products employed in the present invention are water-soluble. These water-soluble dyes are particularly applicable for dyeing spun viscose rayon and cotton goods in shades and levelness comparable to those previously obtained by vat acid processes or by using leucoesters of vat dyes.

I claim:

1. A process for the preparation of benzanthroneanthraquinoneacridine compounds from water-soluble sulfonic acid derivatives of benzanthronylaminoanthraquinone compounds selected from those having the general formula:

(a) Bz-NH-Aq,

(c) X-Aq-NH-Bz-NH-Aq-X, and

(d) X-Bz-NH-Aq-NH-Aq-X, in which formulas Bz stands for benzanthronyl, Aq for anthroquinonyl and X is selected from the group consisting of hydrogen, -NH-Bz-, -NH-Aq, -NH-Bz-NH-Aq, -NH-Aq-NI-I-Bz and -NH-Aq-NH-Aq, each benzanthronyl radical in said compounds forming with an aminoanthraquinonyl radical a nucleus of the formula:

in which X stands for the same as above, there being not more than three Bz radicals and not more than a total of five Aq and B2 radicals in each complete molecule; in each case where the benzanthronyl radical is attached to a second anthraquinonyl radical in the molecule, it is through its 9-position to an alpha position of said second anthroquinonyl radical; the anthraquinonyl radicals when connected to each other directly through -NH- are so connected through a linkage selected from the group consisting of alpha-alphaand alpha-beta-imino linkages, and simple substitution products of said benzanthronylaminoanthraquinone compounds in which the substituents are non-sulfonatable under the conditions employed in the preparation of these water-soluble compounds, and prior to sulfonation there being no substituent in the rings A and B; said compounds containing from 1 to 3 sulfonic acid ($0 M) groups, there being at least one sulfonic acid group per benzanthronyl radical in the molecule, in which M stands for H, alkali metal (more particularly Na and K) and ammonium, which comprises vatting said benzanthronylaminoanthraquinone compounds in an alkaline reducing medium.

2. The process of claim 1 in which said benzanthronylaminoanthraquinone compound is dyed on textile material in the vatting procedure simultaneously with its conversion to the acridine.

3. The process of claim 1 in which the alkaline reducing medium comprises aqueous caustic alkali and alkali metal hydrosulfite. 4. A process for dyeing cellulosic fibers with the watersoluble sulfonic acid derivative of a benzanthronylaminoanthraquinone compound according to claim -1, which comprises applying said compound to the cellulosic material from an aqueous caustic alkali and alkali metal hydrosulfite vat.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Fox: Vat Dyestuffs and Vat Dyeing, 1947, pages 20 and 21, John Wiley & Sons, Inc., New York, NY.

I. TRAVIS BROWN, Acting Primary Examiner.

ABRAHAM H. WINKELSTEIN, NORMAN G. TORCHIN, Examiners.

J. HERBERT, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,254,955 June 7, 1966 Joseph Deinet It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column ll, lines 1 to 23, the formula should appear as shown below instead of as in the patent:

. A a B X X \K a Signed and sealed this 1st day of August 1967 (SEAL) Attest:

EDWARD MQFLETCHER,JR@ EDWARD J BRENNER Attesting Officer Commissioner of Patent 

1. A PROCESS FOR THE PREPARATION OF BENZATHRONEANTHRAQUINONEACRIDINE COMPOUNDS FROM WATER-SOLUBLE SULFONIC ACID DERIVATIVES OF BENZANTHRONYLAMINOANTHRAQUINONE COMPOUNDS SELECTED FROM THOSE HAVING THE GENERAL FORMULA: (A) BZ-NH-AQ, (B) X-BZ-NH-AQ-NH-BZ-X, (C) X-AQ-NH-BZ-NH-AQ-X, AND (D) X-BZ-NH-AQ-NH-AQ-X, IN WHICH FORMULAS BZ STANDS FOR BENZANTHRONYL, AQ FOR ANTHROQUINONYL AND X IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, -NHR-BZ-, -NH-AQ, -NH-BZ-NH-AQ, -NH-AQ-NH-BZ AND -NH-AQ-NH-AQ, EACH BENZANTHRONYL RADICAL IN SAID COMPOUNDS FORMING WITH AN AMINOANTHRAQUINONYL RADICAL A NUCLEUS OF THE FORMULA: 